Liquid crystal display devices have come into use in recent years as display devices, such as color television sets and monitors for personal computers. In such liquid crystal display devices, a gap of about 1-10 μm is formed between two transparent panels of glass, for example, that are provided with transparent electrodes, and a liquid crystal substance is enclosed in the gap to form a liquid crystal layer. An electric field is then applied to the liquid crystal layer through the electrodes, thereby orienting the liquid crystal substance in order to control transmission and non-transmission of backlight rays to display an image.
If the thickness of the liquid crystal layer is not consistent in such a liquid crystal display device, display irregularities and contrast anomalies may result. For this reason, in the past, beads of silica particles, metal oxide particles, thermoplastic resin particles or the like, having a uniform particle size distribution, have been placed between the panels as spacers in order to maintain a consistent gap between the panels and maintain a fixed thickness for the liquid crystal layer.
However, since liquid crystal spacers obtained using such particles (particulate spacers) are situated on the panel by dispersion, they are not anchored onto the panel surfaces, and therefore vibrations propagated in the liquid crystal display device can displace the particulate spacers and cause display variations. In addition, because the particulate spacers are situated by dispersion it is not possible to achieve precise placement to obtain a consistently even distribution, and the particulate spacers may become situated at undesired sections, leading to display defects including display variance and dropouts.
One strategy aimed at avoiding the problem of displacement of the particulate spacers has been to cover the surfaces of the particulate spacers with a deposited layer comprising a low-melting-point synthetic resin or wax. However, because the particulate spacers forming the deposited layer are also placed on the panel by dispersion, it is impossible to avoid the problem of uneven distribution.
Other methods devised to solve the aforementioned problem include methods of forming the liquid crystal spacers by coating an ultraviolet curing resin onto one panel, and then drying, exposing and developing (photolithographic methods). Since such methods allow formation of patterns for liquid crystal spacers at the desired locations and generally can provide adhesive force suitable for panels, they are able to improve the problems of abnormal orientation and reduced contrast, compared to particulate spacers.
Such photolithographic methods, however, require removal of the undesired sections after the entire panel surface has been coated with the spacer material, and this not only increases material loss but also adds steps for development and release, thus lengthening the manufacturing line. In addition, photolithography plates must be prepared for different products in order to form the spacers at the desired locations, thus complicating the process. Also, with increasing product sizes of liquid crystal display devices in recent years, it has become ever more difficult to evenly coat the spacer materials and prepare appropriate plates for the larger sizes.
Ink jet printing devices of the kind described in Patent document 1 have been proposed recently for formation of wirings on printed circuit boards and the like. Ink jet printing devices allow direct patterning from electronic data such as CAD data, and are therefore advantageous by eliminating the need to prepare photolithography plates. Moreover, the volume of droplets discharged from the head can be consistently controlled, thus helping to avoid thickness irregularities in the formed film pattern.
The use of ink jet printing devices in the production of color filters with spacers has also been proposed (see Patent document 2). In such methods, spacers are formed on color filters by ink jet printing, and the color filters with the spacers are used as plates between which the liquid crystals are sandwiched.                [Patent document 1] Japanese Unexamined Patent Publication No. 2003-80694        [Patent document 2] Japanese Unexamined Patent Publication No. 2001-83524        